In a mechanical seal device installed in a common device such as pump and agitation apparatus, a pipe for drain or flushing and the like is often connected by screwing in a bore (opening) for piping, formed on a flange portion formed in a metallic member such as seal case (for example, Japanese Unexamined Patent Publication No. 2009-138867 (Patent Document 1) and Japanese Unexamined Patent Publication No. 2008-82354 (Patent Document 2)). In this configuration, metal is exposed in an inside space both in a bore penetrating portion where the bore is formed on the metallic flange portion and a pipe connecting portion via the flange portion.
On the other hand, in a device such as pump and agitation apparatus, high corrosion resistance may be required for the inside space and a specification in which metal is not exposed (nonmetallic specification) may be required, for characteristics of a processing object and the like. In these cases, same specifications are also required in a mechanical seal device to be installed.
Therefore, for example, the flange portion is formed by high corrosion resistant metal such as HASTELLOY® material (HASTELLOY is registered trademark of Haynes International Inc in US), titanium material and the like in a mechanical seal device for a device in which corrosion resistance is particularly required, such as glass lining pump and glass lining agitation apparatus.
Also, when high corrosion resistant metal is too expensive to use in terms of cost or when there remain problems in corrosion resistance even with high corrosion resistant metal, metallic flange portion surface (metal-exposed face) may be subjected to lining application with resin, such as PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxy resin, perfluoroalkoxy alkane) and PEEK (polyetheretherketone).    [Patent Document 1] Japanese Unexamined Patent Publication No. 2009-138867    [Patent Document 2] Japanese Unexamined Patent Publication No. 2008-82354